[wpcote108]

I have coolant in the oil on my 2007 Camry. I replaced the radiator and unbeknownst to me had a small drip from the bottom hose/radiator connection. The end result is that the engine overheated and I am looking at doing a head job. Any advice out there? To do or not to do...? Otherwise, the car is just an anchor! Thanks in advance!

 

[ukrkoz]

Sure. Are you DIYing it?
Remove head and send it to machine shop to resurface. Do NOT just swap out gasket. If head warped, you WILL have problem again. They might as well re set valves in valve seats and replace stem seals.
Now. You have head off, right? Drop oil pan and undo connecting rods from the bottom. Carefully, not to scratch anything, remove pistons.
Place white sheet next to car and mark on it everything - which piston goes where, it all has to go back exactly same way and directions. You can't take say #1 piston and place it into #3 cylinder. Also, connecting rods lower pieces must go back just as they were before.
Replace connecting rod bearings with original size and replace rings with original size. If you car had no issues with oil consumption. If it did, replace pistons with new design one.
Go to parts store and rent honing tool. Re-hone cylinder bores.
Et voila. You pretty much ave new engine.

 

[wpcote108]

My plan is to do it myself... I rebuilt a few engines back in the 70's but nothing this complicated. When I decide to do it, I have a buddy with a shop who said that IF the head is warped, then either toss it and get a used head OR heat the head up to 400 degrees and press it back into flat, then resurface the face. If that is not done, he says the cams will be subject to undue strain and cause a whole host of other problems down the road... So yes, I will plan on doing the head right... including using Time-Cert threads in the block.
As far as new pistons and rings, boy, I dunno! If that can wait for a future project, then that would be best. I don't mind adding a quart or three between oil changes ( 10,000 miles with synthetic).
Question: Since everything was running fine a few days ago, Do I need to replace the cam bushings with originals or can I just replace what is there? Also, I will need a top end gasket set... the joys of car ownership!

 

[ukrkoz]

Look, I had this job done several times, once just in street corner.
It is VERY simple. Only needs some attention and have everything marked. Hence white sheet, as you can write on it. And, lay items down on it the way they came out.
Honestly, I had multiple heads rebuilt and I have never ever heard of pressing an aluminum head back into anything. But, if this is the way, then this is the way. I worked as tool and die(dye?) maker for years, I'd not be pressing aluminum in any direction.
Thing is, you are already there, as you have head off. Pulling pistons out is literal cakewalk, as far as you have pan dropped.
That's me. It's your time, money, and lower back pain. It'd have been rather wasteful to have this done and, gods save, to have to do over because now she started taking oil (bad rings and crank bearings and poor design pistons) Took me slow pace 8 hrs to do such job myself.

 

[wpcote108]

Thank you for your thoughtful response! I appreciate your advice and expertise. If I were to go the route of ordering new pistons, which ones shall I order? What do you recommend? Also, I ask you a question about the camshaft bearings… I would like to hear your opinion on this since you are a tool and die expert. Thank you

I see what you are saying now.... It is burning a little oil, but not bad. Are you saying to remove pistons from the top of engine once the connecting rods are removed? Or though the bottom? I am thinking i can push the pistons out through the top.

Can I ask your advice if I am getting stuck?

 

[ukrkoz]

1. I would NOT be pressing head to start with. It is aluminum. Not stainless steel, it does not like being bent and rebent. Of course, your friend should have better knowledge on that. Simple mating surface re surfacing should suffice. That, pretty much, answers your question - why would you be messing with camshafts? A head that warped so much that it influenced cam jourlnals should be tossed, not repaired. Besides, you can easily review cam bearings condition after head removal. Valve stem seals - definitely replaced.
2. Toyota re designed pistons due to excessive oil consumption on hybrid engines. Allegedly, that was the case for hybrid engines only, as their pistons are different. If your engine was tight and did not use oil, then don't worry about pistons. Now, new rings will definitely not hurt. If your engine did burn oil, you want to talk to dealer if there were updated pistons for your particular engine. They have larger oil channels and rings are different. Again, if that was not an issue, don't mess with it.
Hone and ring compressor/removal tools are ready rentable from any parts store. Just don't score pistons when removing rings.
Heck, you could simply pull pistons out and soak them, with rings on, in kerosine overnight, to remove any crud and for rings to spring back.
Cylinder condition will have ot be assessed after head removal. I'd have replaced chain tensioner same time. Tensioner and guides. My mech would have replaced water pump also. He's very adamant about replacing as much as possible "while you there". Crap tends to happen after a job was done. So why not to do it all anyway.
Now, all this is going to cost you. Head machining, parts. It may be more cost efficient to actually get a used engine. As, when overheated, seals tend to go bad and start leaking. Certified used engine from Japan would have been ideal but you know, how much fraud goes there.
Ultimately, it is your decision, how to proceed.

 

[wpcote108]

Honestly, I have not had the car that long to know IF it is using oil at all... I had the same Camry years ago and it did use a little oil.
I am not sure what yor point was about soaking pistons and then having the rings "spring back". Can you please clarify?

 

[ukrkoz]

At a 156 000 miles you DO have carbon build up on pistons, valves and rings. You'd be the first in the history of automobiles not to. And what that build up does, it locks rings in grooves. As I do not know how many miles your car has. Simple math - 2007 is 13 yo car x 12 000 miles year average = 156 000 miles.
I don't mind adding a quart or three between oil changes ( 10,000 miles with synthetic).
1 qrt per 1200 miles is considered excessive by Toyota.

 

[wpcote108]

The car has 220k miles. I see what you mean now... well if I go to the trouble of taking out the pistons, I will at least replace them and new rings, of course.

 

[ukrkoz]

As always, it's personal choice for everyone.
Complexity boils down to how hard is oil pan to remove. I had it done on Olds, on Mitsubishes twice. Slow pace, no frill work.

 

[diesel-man]

It depends on how hot it got. Did it just overheat, you pull over and let it cool down....or did it get so hot that it would barely run? Will it run now for half a minute? If not, the compression rings are toast. Did it look like a steam engine when it was in the middle of overheating?

With 220K miles, it would give more "piece of mind" to put a used engine in it, if you could find one with 100K. I have seen an engine get so hot that the piston rings lost their tension, and didn't have enough compression to run correctly.

After the head is off, you can have a machine shop put a "straight edge" on it and see if it is warped. Look down in each of the cylinders and see if one of them has a crack halfway down....you'll have to rotate the engine a half turn to look at the other 2.
I hope for you, all the best....

 

[ukrkoz]

Rotate crankshaft/pistons, of course.....not engine.

 

[wpcote108]

Well I only drove a couple miles before I noticed the temperature gage was pinned up to the top. I ammediately pulled over and let it cool down before starting it again and driving one more mile to get home. It will run… But there is a fair amount of coolant in the engine oil. My plan is to remove the head and assess the damage before deciding whether or not I want to move forward with it. It being reworking the head and replacing pistons and rings

 

[diesel-man]

It sounds as if the rings are OK, as far as compression, have the head checked for being flat. Make sure that you find that "aha", like the spot on the head gasket, and look for cracks anyway. If cracked, according to ebay…..the head is the same for standard Camry and Hybrid (double check this) and should be found at most salvage yards. Anything else that is close by in the process, save yourself the future trouble and replace it, unless it looks too good to change out. A water pump @ 250K would suck.... Just don't have it apart too long 'fore the "chillen's" strew the parts all over the yard, and take 100 pictures if you have to. A lot can get forgot while the head is at the machine shop.

Yes, rotate the crank and not the "engine" to check the cylinder walls....those "Left Coasters"....

 

[ukrkoz]

Also, when you turn crank, go ONLY in normal engine rotation direction. Or, you WILL bust main seals.

 

[diesel-man]

Also, when you turn crank, go ONLY in normal engine rotation direction. Or, you WILL bust main seals.

Being a mechanic...I just know to not to rotate the crankshaft backwards...I didn't think to include that. But actually I would not rotate it backwards for a different reason....in case the hydraulic chain tensioner for the timing chain, would possibly get fully retracted and the chain slip a tooth. Of course this may not apply to this engine, but as a general statement, it is just a good practice, to stay out of trouble. I found over the years that the sign of any good mechanic/carpenter/service person, etc., is after you get in trouble, having the ability to craft a solution and correct the situation in a workmanship like manner.

 

[ukrkoz]

He removes head. No chain. He can - accidentally, as I did - turn wrong way.

 

[wpcote108]

Thanks guys. I appreciate the words of advice! Like I said, I rebuilt a couple of engines in the early 70's but those were dinosaurs compared to this engine and I would like to know that if i get stuck in any way, that you will be there to hold my hand... I should be tearing into the head this week.... hopefully.

 

[ukrkoz]

Engine is engine. Head, block, covers, pan, manifolds. Nothing really changed. All changes are outside of that.

 

[wpcote108]

Greetings friends! I got the head off. Inspected the cylinder walls and found minimal scratches. No cracks in cylinder walls. I found a place where the head gasket was breached between 2 and 3. The out of flatness MAX is .008. I measured the head at .007, so I am hoping all it needs is a little work at the machine shop. They can make sure no cracks in head. The valves all seal nicely, but I will remove and re-seat after head comes home. I will post a few pics when I get a chance.
Questions: I am ordering STD pistons and rings as well as rod bearings. Do I need to be watchful of the gap in the ring when placed inside the cylinder and measured? Pistons measure almost 3 1/2 " in diameter. Also, how do I know that the engine was not rebuilt previously? Finally, do I need to flat sand the aluminum block head?